Apparatus for hardening the axial end of a workpiece



Aug. 22, I197 APPARATUS FOR HARDENING THE AXI 2 sheetswsheet 1 Filed March 8, 1965 KR ml mm mm :11: :11: III v o. MN T R E B m 2 2. 3 w: N9 02 .vm mm B /O OD KW? NE Oh mm .W T o9 Lfi wm mm 3 I h J K]: mm v2 NM. mg 0: 02 No. Q 1 mm Wu om om .wm N2 m mm wm om Nv om I ow Nw @m w NR. Mm ON N N N. q mm @E ATTORNEYS W67 N. R. BALZER 3,3372% APPARATUS FOR HARDENING THE AXIAL END OF A WORKPIECE o I 5; q l w W) m g 3 i w o. T- Q h 7 U o O h N Z 9 mlg I :3 I am 0 m N g m INVENTOR. o NQRBERT R. BALZER w 0 BY ATTORNEYS United States Patent of Ohio Filed Mar. 8, 1965, Ser. No. 437,918 7 Claims. (Cl. 2666) This invention pertains to the art of induction heating and more particularly to an apparatus for hardening the axial end of a workpiece.

The invention is particularly applicable to an apparatus for hardening the end of a motor vehicle axle shaft, and it will be described with particular reference thereto; however, it will be appreciated that the invention has much broader applications and may be used for heating and/ or hardening other workpieces.

An axle shaft for a motor vehicle often includes, at one end thereof, a protuberance, known in the trade as a button, which is used for connecting the axle shaft within the dilferential of a motor vehicle. In order to increase the life of this button, it must be surface hardened in generally the same manner as the other parts of the axle shaft. Heretofore, hardening of this button has caused processing difliculties. I

The inductor for hardening the axle shaft is a circular inductor having a central opening, somewhat larger than the diameter of the shaft and adapted to surround the shaft during the heating operation. This inductor could not be used to harden effectively the button, especially the flat, axially facing, surface of the button. Consequently, a separate inductor was required to perform th1s part1cular hardening operation. Heretofore this separate inductor was pancake-shaped and somewhat resembled the burner on an electric range. This pancake-shaped inductor was mounted in a fixed position and the flat end surface of the button was positioned directly opposite the inductor, with the axis of the shaft being substantially perpendicular to the flat surface of the inductor. This procedure was not satisfactory. Since the spacing between the end surface of the button and the inductor had to be accurately controlled, the dimensional variations between this surface and other points on the axle shaft prevented such other points from being used to locate thesurface of the button with respect to the inductor. Consequently, it was necessary to visually space the button from the inductor or use a feeler gage to space the button accurately from the flat face of the inductor. This involved a substantial effort and increased the cost of hardening the shaft button.

Since the flat surface of the inductor was only slightly spaced from the flat end surface of the button, there was no way of rapidly quenching the button surface while it remained in the heating position. For this reason, the shaft had to be removed from its heating position before the button could :be quenched to provide the necessary surface hardness. To obtain uniform hardness and a uniform hardness pattern, it was necessary to accurately control the time between heating and quenching of the button. It was difficult to remove the shaft and quench the button without substantial variations in this time.

These and other disadvantages of prior apparatus for hardening the end of a workpiece have been completely overcome by the present invention which is directed toward an apparatus for hardening the end of a workpiece, such as the button on an axle shaft, without requiring substantial effort in locating the workpiece and without requiring removal of the workpiece before it is quenched.

In accordance with the present invention, there is provided an apparatus for hardening the axial end of a workpiece. This apparatus comprises an inductor having a central opening, first and second axial ends, and energizing leads adapted to be connected to a high frequency power source, a locator abutment, means adjacent the first axial end of the coil for moving the abutment between a first position Where the abutment extends through the inductor opening and protrudes from the second axial end of the inductor a predetermined distance to form a locator for the axial end of the workpiece with respect to the inductor and a second position where the abutment is retracted from the first position. Also included in the apparatus is a means for introducing quenching fluid into the inductor opening when the abutment is in the second position whereby the fluid flows through the opening and onto the axial end of the workpiece for quenching the same.

By utilizing an apparatus as defined above, the axial end of the workpiece can be moved to a position determined by the abutment extending through the inductor. After the workpiece is clamped in this position, the abutment is withdrawn from the inductor and the inductor is energized to heat the workpiece. Thereafter, a quenching fluid is directed through the opening in the inductor which is vacated by the retracted abutment. This provides a convenient and highly eflicient arrangement for locating and quench hardening the axial end of a workpiece, such as the button on the end of an axle shaft.

The primary object of the present invention is the provision of an apparatus for hardening the axial end of a workpiece which apparatus is eflicient in operation and economical to produce.

Another object of the present invention is the provision of an apparatus for hardening an axially facing flat surface on a rod-like workpiece, which apparatus accurately positions the flat surface from the surface of a heating inductor positioned opposite thereto.

A further object of the present invention is the provision of an apparatus for hardening an axially facing flat surface on a workpiece, which apparatus quench hardens the flat surface without requiring removal of the workpiece from the heating position.

These and other objects and advantages will become apparent from the following description used to illustrate the preferred embodiment of the invention as read in connection with the accompanying drawings in which:

FIGURE 1 is a side elevational, partially cross-sectioned view illustrating, somewhat schematically, the preferred embodiment of the present invention;

FIGURE 2 is an enlarged, partially cross-sectioned view illustrating certain operating characteristics of the preferred embodiment shown in FIGURE 1; and,

FIGURE 3 is a partial view taken generally along line 3-3 of FIGURE 2.

Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only and not for the purpose of limiting same, the figures show an apparatus A for hardening the protuberance or button B on the end of an elongated workpiece, such as axle shaft C. Basically, apparatus A includes a lower frame 10 for supporting a clamping and rotating device 12 and a locating, heating and quenching mechanism 14.

In accordance with the illustrated embodiment of the invention, the clamping and rotating device comprises a relatively fixed support 20 secured onto frame 10 by an appropriate bracket 22. Within the support 20 there is provided a spindle 24 rotatably mounted on spaced bearings 26, 28. Adjacent one end of spindle 24 there is provided a drive flange 30 having secured thereto a sprocket 32 adapted to be rotated by a chain 34, or a similar device, which is driven by motor 36. Spindle 24 is provided with an axially extending workpiece passage 40 and a collet 4-2. The collet is somewhat schematically illustrated and includes a plurality of circumferentially arranged gripping segments 44, each having an outwardly facing cam surface 46. A ring shaped piston 50 encircles segments 44 and has a conical cam surface 52 which coacts with the cam surfaces 46 on the individual segments 44. Movement of the ring piston 50 toward flange 3t forces segments 44 radially inward to clamp against the outer surface of workpiece C, as is conventional in the art of clamping workpieces to be inductively heated. A rearwardly extending flange ring 54 is reciprocally mounted within fluid chamber 56 so that an increased fluid pressure within the chamber will force the ring piston 50 in the workpiece clamping direction. At the forward end of piston 50 there is provided a coil spring 58 which biases the piston 50 against the fluid within chamber 56. A conduit 60, schematically represented as a dashed line, connects the chamber 56 with conduit 62. Hydraulic pressure may be created within the chamber 56 to actuate the piston 50 by supplying pressurized fluid to conduit 62 from a pump, not shown.

It should be appreciated that the illustrated embodiment of the clamping and rotating device is only representative of many such devices which would be appropriate for axially clamping the workpiece C and rotating the same for the purpose to be hereinafter described in detail.

Referring now to the locating, heating and quenching mechanism 14, this mechanism includes an inductor 70 having a central opening 70:: and an internal coolant passage 70b. As is common practice in the art, a coolant, such as water, is circulated through passage 70 for the purpose of reducing the operating temperature of the inductor. As best illustrated in FIGURE 3, inductor '70 is connected by spaced power leads 72 onto an appropriate high frequency power source, schematically represented as a generator 76. The inductor 70 has a flat axially facing surface 78 which is fixedly secured with respect to the workpiece passage 40 by an inductor support bracket 80 fastened, by bolts 82, onto a locating and quenching head 90.

The locating and quenching head 90 includes a housing 92 supported directly onto lower frame and having a longitudinally extending bore 94, which is generally in alignment with the workpiece passage 40 and opening 70a. At the forward end of housing 92 there is provided an extension 96 having a larger, rear bore 100 and a' smaller, forward bore 102 which bores 100, 102 are generally concentric with bore 94. An outlet aperture 104 in the smaller bore 102 is positioned directly opposite opening 70a in inductor 70. Reciprocally mounted within housing 92 and extension 96 there is provided a locator assembly 110 including a carrier 112 with a lower rack gear 114. A pinion gear 116 secured onto shaft 118 by an appropriate key 120 is adapted to mesh with rack gear 114 whereby rotation of shaft 118 reciprocates carrier 112. A bore 122 extends substantially the complete length of carrier 112 and receives a shank 130 of a rod 132. The rearwardmost portion of rod 132 terminates in a threaded extension 134 having a head 135 for rotation of the rod 132. The extension 134 is threadably received within an aperture 136 so that a lock nut 138 can secure the rod 132 in a variety of axial positions with respect to carrier 112. The inwardmost position of carrier 112 is limited, in accordance with the illustrated embodiment of the invention, by a washer 139 fixedly secured onto the end of the carrier and adapted to abut the rearward end of housing 92. It is appreciated that other such stopping arrangements could be provided. A bearing seal 140 supports the assembly 110 at one end and seals the bore 94 with respect to carrier 112 and a bearing seal 142 supports the assembly 110 at the other end and seals the rod 132 with respect to bores 94, 100.

At the forwardmost end of rod 132 there is provided a locator tip 150 having a size generally matching the internal configuration of bore 102. The terminal end of tip 150 forms an abutment 152 which provides the workpiece locating arrangement for mechanism 14, in a manner to be hereinafter described in detail. Bore is provided with a radially extending port 160 having a nipple 162 for communicating bore 100 with a line 164, schemati cally represented as a dashed line in FIGURE 2, which line is connected to the output of a quench supply 170.

In operation of the locating, heating and quenching mechanism 14, the carrier 112 is reciprocated by shaft 118 toward the inductor 70 to a position determined by the washer 139. This protrudes locator tip through aperture 104 and through inductor opening 70a. By properly adjusting the axial position of rod 132 within bore 122, by rotating head 135, the abutment 152 at the end of the tip will extend through the inductor 70 a distance x as shown in FIGURE 2. This distance x is the desired spacing between the axial surface D of button B and the axial surface 78 of inductor 70. After the abutment 152 is properly positioned with respect to inductor 70, the workpiece C is forced through passage 40 until the surface D contacts abutment 152. Then, hydraulic fluid is introduced into chamber 56 and segments 44 clamp the workpiece in this located position. The shaft 118 is rotated to retract tip 150 from opening 70a and aperture 104 so that the tip is in the position shown in FIGURE 2. This leaves the surface D accurately positioned with respect to the inductor surface 78. Motor 36 then rotates the workpiece and inductor 70 is energized by generator 76. This inductively heats the button B to the desired hardening temperature. After a predetermined time, which allows for equalization of the heat within the button B, the inductor is de-energized and a quenching fluid, such as water or oil, is introduced from supply 170 through port into the bore 100. From this bore, the quenching fluid flows through aperture 104, opening 70:: and impinges upon the heated button B. In this manner, the workpiece is immediately quenched without requiring removal of the workpiece from its heating position. After the button B is quenched, pressure is released from the fluid within chamber 56 and spring 58 releases the workpiece C. This cycle is repeated for each workpiece to be heated.

The present invention has been described in connection with certain structural embodiments; however, it should be appreciated that various changes may be made in these structural embodiments without departing from the intended spirit and scope of the present invention as defined by the appended claims.

Having thus described my invention, I claim:

1. An induction heating apparatus for hardening the axial end of a workpiece, said apparatus comprising: an inductor having a central opening, first and second axial ends, and energizing leads adapted to be connected onto a high frequency power source; a locator abutment; means adjacent said first axial end for moving said abutment between a first position where said abutment extends through said opening and protrudes from said second axial end a predetermined distance to form a locator for the axial end of said workpiece with respect to said second axial end of said inductor and a second position Where said abutment is retracted from said first position; and, means for introducing quenching fluid into said inductor opening when said abutment is in said second position whereby said fluid flows through said opening and onto said axial end of said workpiece.

2. An apparatus as defined in claim 1 including a housing adjacent said first axial end of said inductor and having a bore coaxial with said opening and having an aperture facing said opening, and said locator abutment being a rod reciprocally mounted within said bore.

3. An apparatus as defined in claim 1 wherein said fluid introducing means includes means for introducing quenching fluid into said bore when said rod is in said second position, and means for allowing flow of said fluid from said aperture toward said opening.

4. An induction heating apparatus for hardening the axial end of a workpiece, said apparatus comprising: an inductor having a central opening, first and second axial ends, and energizing leads adapted to be connected onto a high frequency power source; a housing mounted adjacent said first axial end and having a bore generally coaxial with said opening; said bore having a terminal aperture facing said opening; a rod; means for reciprocating said rod within said bore between a first position Where said rod extends through said aperture, through said opening and protrudes from said second axial end a predetermined distance to form a locator for the axial end of said workpiece with respect to said second axial end of said inductor and a second position where said rod is retracted from said first position; and means for introducing quenching fluid into said inductor opening when said rod is in said second position whereby said fluid flows through said opening and onto said axial end of said workpiece.

5. An induction heating apparatus for hardening the axial end of a workpiece, said apparatus comprising: an inductor having a central opening, first and second axial ends, and energizing leads adapted to be connected onto .a high frequency power source; a housing mounted adjacent said first axial end and having a bore generally coaxial with said opening; said bore having a terminal aperture facing said opening; a rod; means for reciprocating said rod within said bore between a first position where said rod extends through said aperture, through said opening and protrudes from said second axial end a predetermined distance to form a locator for the axial end of said workpiece with respect to said second axial end of said inductor and a second position where said rod is retracted from said first position and spaced from said aperture to vacate a portion of said bore adjacent said aperture; and means for introducing quenching fluid into said vacated portion of said bore when said rod is in said second position whereby said fluid flows from said aperture, through said opening and onto said workpiece.

6. An induction heating apparatus for hardening the axial end of a workpiece, said apparatus comprising: an inductor having a central opening, first and second axial ends, and energizing leads adapted to be connected onto a high frequency power source; a housing mounted adjacent said first axial end and having a bore generally coaxial with said opening; said bore having a terminal aperture facing said opening; a rod; means for reciprocating said rod within said bore between a first position where said rod extends through said aperture, through said opening and protrudes from said second axial end a predetermined distance to form a locator for the axial end of said workpiece with respect to said second axial end of said inductor and a second position where said rod is retracted from said first position; means for introducing quenching fluid into said bore when said rod is in said second position; and means for allowing flow of said fluid from said aperture toward said opening whereby said fluid flows through said opening and onto said workpiece.

7. An induction heating apparatus for hardening the axial end of a workpiece, said apparatus comprising: an inductor having a central opening, first and second axial ends, and energizing leads adapted to be connected onto a high frequency power source; a housing mounted adjacent said first axial end and having a bore generally coaxial with said opening, said bore having a terminal aper' ture facing said opening; a rod with a longitudinal axis; means for axially reciprocating said rod within said bore to a first position where said rod extends through said aperture, through said opening and protrudes from said second axial end a predetermined distance to form a locator for the axial end of said workpiece; means for moving said axial end of said workpiece against said rod and on an axis parallel to the longitudinal axis of said rod; means for clamping said workpiece when said workpiece is against said rod; means for axially retracting said rod from said clamped workpiece; and, means for introducing quenching fluid into said inductor opening when said rod is retracted whereby said fluid flows through said opening and onto said workpiece.

References Cited UNITED STATES PATENTS 241,680 5/1881 Lorenz 266-6 2,240,493 5/ 1941 Denneen 266-4 2,419,619 4/1947 Wood 219-1057 XR 2,449,944 9/1948 Johnson 266-4 2,504,198 4/1950 Jagen 266-4 2,623,836 12/1952 Noren 148-150 2,632,841 3/1953 Wharfi 219-1057 3,143,628 8/1964 Golden.

3,271,019 9/1966 Armstrong 266-8 XR J. SPENCER OVERHOLSER, Primary Examiner.

R. S. ANNEAR, Assistant Examiner. 

1. AN INDUCTION HEATING APPARATUS FOR HARDENING THE AXIAL END OF A WORKPIECE, SAID APPARATUS COMPRISING: AN INDUCTOR HAVING A CENTRAL OPENING, FIRST AND SECOND AXIAL ENDS, AND ENERGIZING LEADS ADAPTED TO BE CONNECTED ONTO A HIGH FREQUENCY POWER SOURCE; A LOCATOR ABUTMENT; MEANS ADJACENT SAID FIRST AXIAL END FOR MOVING SAID ABUTMENT BETWEEN A FIRST POSITION WHERE SAID ABUTMENT EXTENDS THROUGH SAID OPENING AND PROTRUDES FROM SAID SECOND AXIAL END A PREDETERMINED DISTANCE TO FORM A LOCATOR FOR THE AXIAL END OF SAID WORKPIECE WITH RESPECT TO SAID SECOND AXIAL END OF SAID INDUCTOR AND A SECOND POSITION WHERE SIAD ABUTMENT IS RETRACTED FROM SAID FIRST POSITION; AND. MEANS FOR INTRODUCING QUENCHING FLUID INTO SAID INDUCTOR OPENING WHEN SAID ABUTMENT IS IN SAID SECOND POSITION WHEREBY SAID FLUID FLOWS THROUGH SAID OPENING AND ONTO SAID AXIAL END OF SAID WORKPIECE. 